A conventional table cover as shown in FIG. 4 used for shielding foods or dishes placed on a table for preventing fly bites includes a central rod 41 reciprocatively held in a collar 42, a shielding screen 40a secured on ribs 40 pivotally secured to a runner 4 and the collar 42, and catch 43 resiliently formed in the rod 41 to be engageably locked with a socket 44 formed in the collar 42 when pulling a loop 45 of the rod 41 upwardly for opening the shielding screen 40a. When retracting the screen 40a, the catch 43 of the central rod 41 is disengaged from the socket 44 in the collar 42 when depressing the rod 41 downwardly to close the screen 41a. However, such a conventional table cover has the following drawbacks:
1. The engagement of catch 43 with collar socket 44 is performed at a fixed position on the central rod so that the shielding screen 40a can only be extended to a fixed opening situation, which can not be freely adjusted for an optionally desired diameter suitable for any sized tables or table foods.
2. The stretcher rib 40 pivotally secured to the runner 4 is generally perpendicular to a longitudinal axis of the rod 41 and not formed as an arcuate shape so that once disengaging the catch 43 from the socket 44, the reciprocating operation of the central rod 41 such as for retracting and closing the screen 40a will bear against a strong elastic force exerting on the ribs 40, easily causing a user's tiredness.
The present inventor has found the drawbacks of the conventional table cover and invented the present table cover optionally positioned for adjusting any desired opening diameter of the cover.